Just a head's up that this camshaft adjustment solenoid campaign number 2009100001 was revised in April of 2011. They will no longer cover the replacement of the leaking camshaft adjuster solenoid itself, but they will install the non-wicking harness extension for free. They will also fix/replace components damaged as a consequence of the faulty harness design. You can find this and tons of other service bulletins for our cars at Search Technical Service Bulletins
I just had it done. Before I even asked about it, they told me they would inspect ECU, etc. for oil, and they told me that they would replace any oil-damaged component for free. I was going to replace the leaking magnet myself-I have never before paid a dealer a cent for service outside of warranty-but MB of PDX only charged $25 labor. I wanted OEM for this part, as I see posts that other manufacturers have defects. The local dealer actually charged less for the parts (including center "plug" cap thingy) than the discount online Mercedes dealers do, if you count shipping. Given that I would have also had to get the correct anaerobic sealant, clean up the oily mess, etc. $105, total was a very decent price.